Barbecue grills have been popular for many years with backyard and patio chefs. These grills typically have been heated by charcoal briquettes or by fuel gas. In recent years, portable grills heated by a fuel gas source, such as a propane tank, have become increasingly popular. These gas grills combine the convenience of portability with the use and thermal efficiency of propane, which eliminates the need for lighter fluid, new charcoal at each use, and charcoal disposal.
Portable gas grills typically include a cart, with two or four wheels, that supports a cooking housing. The cooking housing typically consists of a firebox, a cover, and a burner near the bottom of the firebox. It also includes a grate for holding socalled "lava rocks" (pumice stone), a heat distribution plate, or an apparatus that shields the burner tubes from grease drippings and simultaneously vaporizes drippings falling on to the apparatus. That plate or apparatus is typically spaced above the burner in the firebox, and a metal wire cooking grid is positioned well above the plate or apparatus for holding the food to be cooked. Portable gas grills include a portable fuel tank supported by the cart, below the firebox. Features often found on portable grills include side burners for cooking or warming food; warming racks positioned above and to the rear of the cooking grid; rotisserie devices for cooking on a spit above the cooking surface; and condiment racks for holding spices, sauces, and other useful condiments.
Lava rock grates, heat distribution plates and vaporizing structures each act as barriers to the heat transfer from the gas burners at the bottom of the grill lower housing to the cooking grid. It is an object of the present invention to remove these structures, or any other structures, between the burner and the cooking surface and thereby increase heat transfer efficiency. The burner in the present invention is also placed substantially closer to the cooking surface than burners in the prior art. As a consequence of the burner's proximity to the cooking surface and the removal of heat barriers, the heating efficiency of the present invention is significantly increased.
It is another object of the invention to provide a burner shaped to vaporize grease, spread out the flame for even heat distribution, and allow grease to run off the tube without clogging the burner holes in the tube.
It is another object of the invention to provide burner tubes that are easy to insert into and remove from the firebox.
It is another object-of the invention to provide a structure for propagating flames from one burner tube to another burner tube parallel to the first burner tube that does not create a "hot spot" in the grill cooking surface.
Portable gas grills are typically constructed out of cast aluminum. One object of .the present invention is to provide an improved method of manufacture for the grill housing, cart, and burner, through the use of roll-forming technology. The use of roll-forming allows for the manufacturing and marketing of different-sized grills and grill parts without re-tooling of the manufacturing process.
It is another object of the invention to provide a cooking surface with crests and troughs, and apertures in the troughs, to optimize heat transfer and to allow for improved flow of grease drippings, and to contain flare-ups below the cooking surface.
It is another object of the invention to decrease the frequency of grease fires by the general placement of exhaust vents or apertures in the upper portion of the walls of the grease-catching structure located beneath the firebox.
It is another object of the invention to provide an improved rotisserie device for use with the barbecue grill described herein.
Other objects and advantages of the invention will become apparent to those skilled in the art by reference to the accompanying description and drawings.